Jiaozuo brake

Adjustment of the clearance between the brake friction plate and the brake wheel

The safety of a crane is very important, so how to ensure its safety? Its safety performance refers to active safety (the ability to avoid accidents) and passive safety, also known as active safety. In terms of behavior, when a heavy object wants to stop in the air, it needs to be braked, which belongs to active safety, but accidents usually occur at this time. Nowadays, most factories use double pad brakes for crane brakes. When it is necessary to open or brake, the electromagnetic attraction, release, or oil pump start and stop are used to compress or release the elastic force of the brake spring, causing the brake pads to leave the brake wheel or fit onto the brake wheel, achieving the requirements of opening or braking. When a derailment or hook slipping accident occurs (usually when lifting a large heavy object), several staff members who are responsible for monitoring the crane will use tools such as crowbars to increase the pressure on the brake shoes on the brake wheels, in order to achieve emergency braking and prevent the occurrence of the accident or reduce the degree of damage caused by the accident. In some accidents, the staff responsible for monitoring on the bridge crane also took such measures, but did not achieve the corresponding effect. Instead, it was a major accident where the brake cracked and the brake fragments flew out, causing casualties to the monitoring personnel. The function of brakes is not only reflected in cars, elevators, cranes, etc., but also has excellent performance in the operation of various equipment. Its function is manifested in:

1. The brake can act on its own when the elevator power supply is cut off, and the brake shoe holds the brake wheel to stop the elevator from running. The deceleration of the elevator during braking shall not exceed the deceleration generated by the safety clamp stopping the car or the car stopping on the buffer.

2. When the elevator stops running at the station, the brake should be able to ensure that the elevator remains stationary at a rated load of 125-150% and should not be opened before restarting.

3. When the elevator exceeds the speed limit and reaches the operating speed of the speed limiter during operation, the brake first acts and applies braking to the brake wheels, causing the elevator to stop running. The brake of the elevator traction machine must be released when powered on to enable the elevator to operate; When the power or control power supply of the elevator is cut off, or when the elevator runs beyond the limit, exceeds the speed limit, or malfunctions, immediate braking is applied to stop or prevent the elevator from starting, ensuring that the brake can achieve reliable braking in the event of a power outage or various unexpected accidents; When the elevator is running normally, the brakes must be fully released and the brake shoes must not come into any contact with the brake wheels. The brake is one of the most frequently used devices in elevators and has a significant impact on safe operation. The brake is an important component in a vehicle. Whenever there is a problem with the brake, it needs to be addressed immediately. After replacing the brake friction plate, reprocessing the brake drum, or disassembling the brake base plate, the gap between the friction plate and the brake drum must be readjusted. The steps are as follows:

1) Remove the inspection hole cover on the brake drum, loosen the fixing nut of the brake shoe support pin and the nut of the camshaft bracket fastening bolt.

2) Rotate the shoe support pin with the markings on the two pin ends facing inward.

3) By repeatedly twisting the screw shaft of the brake shoe support pin and adjusting arm, the brake friction plate and brake drum are fully fitted. At the adjusted position, slowly tighten the fastening nut of the bracket and the locking nut of the automatic shoe support pin to maintain the position of the brake shoe support pin unchanged (it is possible to press and hold the brake pedal to tighten all the bolts and nuts that have been adjusted on it, provided that the air pressure meets the regulations).

4) Loosen the worm shaft by 1/2-2/3 turns, and the brake drum should be able to rotate freely without colliding with the brake friction plate or other parts. The clearance position between the brake friction plate and the automatic drum: at the brake shoe support pin end, it is 0.25-0.40mm, and at the cam end, it is 0.40-0.55mm. The difference in clearance between the two shoes at the same end should not exceed 0.1mm.

5) After the adjustment is completed, compressed air is introduced into the brake chamber, and the stroke of the push rod should be 25-40mm. The rear wheel automatically adjusts the small worm shaft of the arm, and the stroke of the push rod changes by 5mm with each movement, while the front wheel is 4mm.

6) When the stroke of the push rod exceeds 40mm due to wear of the friction plate, local adjustment can be made (at this time, do not twist the support pin to avoid damaging the original good contact state). The method is to face the worm head of the adjustment arm, tighten the screw clockwise at two places on the front wheel (clearance decreases), loosen counterclockwise (clearance increases), tighten counterclockwise at two places on the rear wheel, and loosen clockwise. Attention, do not use the method of twisting the brake chamber push rod to change the ratio of the push rod for "adjustment".

Two types of diagrams, YWZ4 and YWZ